The present invention relates to a firearm and more particularly to a semi-automatic, two-shot, gas-operated shotgun.
Semi-automatic shotguns are popular with sportsmen who engage in competitive shooting such as clay target shooting. Browning firearms introduced a two-shot Browning double-automatic shotgun in about 1955. This gun was an inertia/recoil operated two-shot having a standard top barrel configuration with a loading port on the bottom left side and an ejection port at the top right side.
Ljutic Industries offered a two-shot gas-automatic shotgun called the xe2x80x9cLjutic Bimatic.xe2x80x9d This shotgun had a standard top barrel designed with a gas system and a recoil spring surrounded by the fore end. A second shell is loaded from the bottom by pulling down on the carrier.
U.S. Pat. No. 3,389,487 to Benelli shows a shotgun having a cartridge loading mechanism with a cartridge magazine in the stock rather than under the barrel which is said by the inventor to improve the balance of the gun. The shotgun has two pivotally connected sections which, through relative pivotal movement, raise cartridges one at a time into firing position.
The early patent to Brondby, U.S. Pat. No. 2,223,671 shows an automatic or semi-automatic firearm of the gas reloading type in which part of the gas is passed through a channel into the barrel into a gas cylinder where it operates a piston and also the ejection and reloading mechanism to perform the ejecting and reloading after each shot.
U.S. Pat. No. 3,631,621 shows an automatic recoil actuated shotgun having a spring-loaded magazine in the stock and the carrier in the receiver which lifts the shells into alignment with the barrel to permit the bolt to move the shell into the barrel for firing.
U.S. Pat. No. 3,919,800 shows a side-loading firearm which is provided with a mechanism associated with a tubular magazine that mates with the barrel. The side-loading opening insures that there is always a cartridge visible through the opening when the gun is loaded to capacity, but that the loading opening is always free for quick reloading when there is room in the magazine. The magazine includes a carrier for lifting cartridges from the loading aperture into the chamber in cooperation with a plurality of latch and stop means to control the timing of the carrier member.
Thus, from the foregoing, it is obvious that there are many automatic and semi-automatic shotguns in the prior art which are operated by gas and recoil spring system. In addition to the above, similar features can be found in such shotguns as the Remington 11-87 and 1100, the Beretta 390 and 391, the Browning Gold Auto and various models by Fabarms, Benelli and others.
There nevertheless exists a need for an improved gas-operated shotgun having unique features which render it reliable, balanced and particularly suited for clay target shooting.
Briefly, the present invention relates to a shotgun which is a two-shot shotgun having a side-loading port, lower barrel configuration and bottom ejection. The first shell is inserted into the loading port and is transferred into the breech and the next shell is inserted into the loading port and rests in the carrier shell space above and rearwardly of the breech. At an intermediate location, the barrel has a plurality of gas exit ports spaced around the barrel which communicate with a gas chamber housing a piston. Gas resulting from the firing of a shell will vent from the barrel entering the chamber and actuating the piston to drive a connecting rod assembly rearwardly to cycle the ejection of the empty shell. The connecting rod assembly operates against a recoil spring and will cycle the next shell into the chamber from the carrier.
A bolt assembly having an upper bolt member and a lower bolt member is positioned in the lower portion of the receiver having a shell extractor on its bottom. The spent shell is ejected from the bottom of the shotgun through the ejection port or by fixed shell retainer pinson the face of the lower bolt which retainer the spent shell cartridge in engagement with the extraction as the bolt moves rearwardly. This is facilitated either by two reciprocal pins on the bottom of the bolt assembly that extend forwardly to receive the shell from above and which retract to allow the spent shell to eject cleanly through the ejection port. Twin locking lugs are located on the opposite sides of the lower bolt member and engage locking lug seats on the barrel. The lugs are released by the rearward movement of the upper bolt member which is forced rearwardly by the connecting rods actuated by the gas piston. The rods operate against the resistence of a recoil spring extending around a tube on a carrier assembly.
The trigger mechanism is unique and has a hammer which is pivoted rearwardly to a cocked position as the bolt moves rearwardly. As the bolt returns under the force of the recoil spring, the hammer is allowed to pivot approximately 45xc2x0 before engaging the sear. The hammer is then in a ready-to-fire position closer to the firing pin for a faster lock time.
The firing pin is driven through a bore in the lower bolt by the hammer. A firing pin block prevents premature automatic firing of a subsequent shell before the locking lugs on the lower bolt are substantially engaged.
Another aspect of the shotgun of the present invention is its modular component assembly. The carrier assembly has its own removable frame as does the trigger mechanism. This is in contrast to most existing semi-automatic shotguns which combine the trigger and carrier mechanisms into a single unit.